The Fiber To The Home (FTTH) can provide a service rate in an order of Gigabit to a user, which is considered as an optimal realization form for future broadband access. However, in actual deployment, there are many bottlenecks for the FTTH, for example, problems such as a high construction cost, difficult wiring, and legal disputes etc. Many operators have realized that in some scenarios optical fibers will terminate at a distance of about 100 meters away from the user, and the original copper wire resources will be reused in “last 100 meters” of the user, and broadband access is implemented through a Digital Subscriber Line (DSL) or other copper wire access technology. A termination point of the fiber is a distribution point, and therefore, such application scenario is referred to as a Fiber To The Distribution Point (FTTDP for short).
The application scenario of the FTTDP is as shown in FIG. 1. The DP device (i.e., node device) is typically deployed in places such as a basement of a room, an inlet connecting hole, an outdoor wall etc. In such places, electricity acquisition of a node device is a big problem. As the node device is close to the user, it may be considered to inversely supply power from a Customer Premise Equipment (CPE for short) to the node device. Support for reverse power supply is used as a particular requirement under the FTTDP application scenario, and at the same time, power supply for a single-path user is required, which can ensure normal operation of the node device.
The node device is required to have low power consumption, and at the same time, in order to better support reverse power supply and based on reasons such as environmental protection and economy, it also requires the node device to support the power-saving mode. One power-saving method thereof is as follows: in some period of time, a user will stop using data services, and at this time, the CPE enters a power-saving mode or power thereof will be turned off. As at this time there will be a long time during which no data transmission is on the link, which may reaches orders of hours, a port corresponding to the node device may stop operation and enter a power-saving mode.
There are many power-saving modes for the node device. One is a nap mode, in which the node device stops data transmission, but it needs to open a receiving function, to receive the CEP data and then wake up. Another is a period sleep mode, in which the node device may stop transceiving, but it needs to wake up timely to detect conditions of data transceiving on the line. In order to enable the node device to wake up in time, these two modes both need to enable the node device to maintain the receiving function to be turned on or wake up timely, and the node device can not to enter a complete sleep state. Therefore, the effect of power-saving is not good, especially when the user stop using the data services for a long time. In addition, the manners for controlling the node device to enter or exit the power-saving mode are also very tedious.